The present invention relates generally to a folded sheet material web and assembly, and in particular, to a specific arrangement of a starter sheet material web for a stack of folded webs. The invention also relates to a method and apparatus for folding the starter web.
It is well known in the field of facial tissue for an uppermost or starter web of a stack of longitudinally folded webs to be folded back on itself so as to provide a centrally located longitudinally folded edge on a top of the stack as described, for example, in U.S. Pat. No. 3,401,927, issued Sep. 17, 1968 to Frick, and assigned to Kimberly-Clark Corporation, the same assignee of the present application. The folded edge, and overlying folds of the starter web, are provided so as to allow a user to easily grasp and withdraw the uppermost web from the stack, which is typically retained within a carton or similar packaging. It is also well known in the art to provide a next lower web interfolded with the uppermost web so that a portion of the next lower web is withdrawn from the stack as the uppermost web is withdrawn. In this way, the next lower web is exposed to the user for successive removal from the stack.
Typically, the overlying folds of the starter web are arranged so that a single uppermost fold extends away from the centrally located longitudinally folded edge and terminates in a free edge proximate the side edge of the stack as shown in Frick U.S. Pat. No. 3,401,927. When arranged in such a configuration, a clip of webs, made from a stack of webs cut to a specified length, experiences what is commonly referred to as a "flying sheets" problem, wherein the top few sheets of the clip fly off the top of the clip as it is transported at high speeds from a saw, where the stack of webs is cut to form the clips, to a cartoner, where the clips are packaged in cartons and the like. Another problem typically encountered with a stack having a web with an uppermost fold terminating in a free edge, whether it be at the side of the stack or at a midpoint, is that the uppermost fold has a tendency to adhere both to a top pull-belt, which is used to urge the stack of webs from a folding board toward the saw, and to hold-down chains, which engage the top of the stack as it passes through the saw. In addition, because the uppermost fold presents two exposed edges, i.e., the centrally located longitudinally folded edge and the outer free edge, the folding process must be closely monitored so as to ensure that the free edge is proximate to the side edge of the stack. If the free edge extends past the side edge, it can be caught on the machinery and the like as the stack is conveyed from the folding board to the saw, and then as the clip is conveyed to the cartoner. Conversely, if the free edge is not aligned with, or falls short of, the side edge, it can present an aesthetically displeasing appearance to the user.
To combat the problem of "flying sheets" and adhesion, facial tissue manufacturers commonly are forced to reduce line speeds and/or incorporate additional manufacturing steps, such as spraying liquids on the top sheets, employing weights to hold the top sheets down, applying antistatic products to reduce static, cleaning surfaces to reduce static, and/or controlling the humidity/temperature in the relevant operating areas. Alternatively, additional folds or webs can be introduced in the top sheets, but with the adverse impact of requiring extra sheets to be dispensed on the initial withdrawal by the user. Therefore, the above-mentioned efforts can result in lower productivity, increased manufacturing costs or waste by the user.
Another problem encountered with a stack having only a single uppermost web is that the web is susceptible to tearing and the like upon removal by a user. This problem is especially acute when the uppermost web is interfolded with a next lower web, as the next lower web applies forces to the uppermost web as it is being withdrawn.